How do I maintain and clean a printer?

Just like computers, printers also collect dust and dirt over time which can staple up and cause opponents to slow down or move incorrectly. Unlike computers, they contain objects that move a lot and so there is also need for mechanical maintenance.

To extend the lifetime and keep the accuracy high of a printer, how can I maintain and clean it?

What is the general advice for outlining a printer? I suppose I need to do this when noticing mistakes?

This will vary greatly depending on what sort of printer you are trying to clean. Most printers will come with instructions specific to them and these must be taken into account for various reasons. Specifically, the design of the printers will cause great variance in the type and style of cleaning that is appropriate with the various portions of the printer.

Generally rules that will apply to most (but not all) printers are these:

1) Don't use compressed (canned) air!

Especially with laser printers, but still valid with most other types, compressed air will blow paper dust, spare toner, and any other foreign objects into the print heads, motors, fuser wires, and many other components that do not work well when buried under fine layers of dust. I learned this one the hard way. Dot Matrix are probably the least susceptible to the problems associated with blown dust simply by nature of their much greater mechanical tolerances and lower expected output quality compared with other printers.

2) Wet/Moist cleaning wipes are OK on the outside only!

Moisture is only slightly less problematic than dust, mostly because it'll probably evaporate. However, moistened wipes will usually smear and leave residue which is not good for electronic's life expectancy. On the outside they're just fine though. And in an office environment it can be good for office hygiene to wipe the shared printers down every once in a while.

3) Do not use solvents on the rollers!

Any sort of solvent or cleaner will generally dry out the paper rollers, decreasing their lifespan, degrading paper handling, increasing jams and other equipment failure. The only liquid that should ever be used on paper rollers is none. Even rubber conditioners will cause the rollers to become more sticky than they should be, causing problems. If the rollers are having trouble, wipe them with a dry rag to remove any built-up paper dust, or order a replacement kit (usually availble for laser printers).

4) Dry wipes are your best friend.

Lint-free towels (old socks are great for this, especially polyester/cotten blends with a fine enough weave) are the best tool for cleaning anything out of printers, for wiping the rollers, and any other use inside the printer.

Good stuff - I'll add...

5) Do not use a domestic vacuum cleaner on a laser printer to clean up toner spills

The toner is so fine it will pass straight through many bags and filters and be recirculated into the air, which is not a good idea. Domestic vacuum cleaners can also generate a lot of static electricity which may damage sensitive components. Service engineers have special 'computer' or 'printer' vacuum cleaners. Use dry paper towels to lift out stray toner.

6) Do not lube any shafts, runners or cogs unless you absolutely have the right stuff and know what you are doing

Using the wrong lubes or greases will attract dust and actually make things worse. Mixed lubes or greases can also react with each other and go hard or sticky.

7) Do not spray solvents into/on dot matrix print heads

If you need to clean the print head of a dot matrix printer (remember those!?), spraying a cleaning solvent onto the head pins will generally liquify any gunked up ribbon ink and then it will run back into the pin guide or internals (solenoids) where the solvent will evaporate, leaving the parts 'glued' together with ink residue. The correct way is to remove the head and then sit it, pin head down, in a small, covered bath of cleaning solvent for an hour or so to let the ink dissolve completely and disperse into the solvent. The head should then be removed and left to dry out with the print pins facing downwards. (And if any of you really need to do this I'm impressed!)